Phenotypic Characterization of 2D and 3D Prostate Cancer Cell Systems Using Electrical Impedance Spectroscopy.

Prostate cancer is the second leading cause of death in men. A challenge in treating prostate cancer is overcoming cell plasticity, which links cell phenotype changes and chemoresistance. In this work, a microfluidic device coupled with electrical impedance spectroscopy (EIS), an electrode-based cell characterization technique, was used to study the electrical characteristics of phenotype changes for (1) prostate cancer cell lines (PC3, DU145, and LNCaP cells), (2) cells grown in 2D monolayer and 3D suspension cell culture conditions, and (3) cells in the presence (or absence) of the anti-cancer drug nigericin. To validate observations of phenotypic change, we measured the gene expression of two epithelial markers, E-cadherin (CDH1) and Tight Junction Protein 1 (ZO-1). Our results showed that PC3, DU145, and LNCaP cells were discernible with EIS. Secondly, moderate phenotype changes based on differences in cell culture conditions were detected with EIS and supported by the gene expression of CDH1. Lastly, we showed that EIS can detect chemoresistant-related cell phenotypes with nigericin drug treatment. EIS is a promising label-free tool for detecting cell phenotype changes associated with chemoresistance. Further development will enable the detection and characterization of many other types of cancer cells.

Theaflavin mitigates acute gouty peritonitis and septic organ injury in mice by suppressing NLRP3 inflammasome assembly.

Activation of NLR family pyrin domain-containing 3 (NLRP3) inflammasome plays important role in defending against infections, but its aberrant activation is causally linked to many inflammatory diseases, thus being a therapeutic target for these diseases. Theaflavin, one major ingredient of black tea, exhibits potent anti-inflammatory and anti-oxidative activities. In this study, we investigated the therapeutic effects of theaflavin against NLRP3 inflammasome activation in macrophages in vitro and in animal models of related diseases. We showed that theaflavin (50, 100, 200 µM) dose-dependently inhibited NLRP3 inflammasome activation in LPS-primed macrophages stimulated with ATP, nigericin or monosodium urate crystals (MSU), evidenced by reduced release of caspase-1p10 and mature interleukin-1ß (IL-1ß). Theaflavin treatment also inhibited pyroptosis as shown by decreased generation of N-terminal fragment of gasdermin D (GSDMD-NT) and propidium iodide incorporation. Consistent with these, theaflavin treatment suppressed ASC speck formation and oligomerization in macrophages stimulated with ATP or nigericin, suggesting reduced inflammasome assembly. We revealed that theaflavin-induced inhibition on NLRP3 inflammasome assembly and pyroptosis resulted from ameliorated mitochondrial dysfunction and reduced mitochondrial ROS production, thereby suppressing interaction between NLRP3 and NEK7 downstream of ROS. Moreover, we showed that oral administration of theaflavin significantly attenuated MSU-induced mouse peritonitis and improved the survival of mice with bacterial sepsis. Consistently, theaflavin administration significantly reduced serum levels of inflammatory cytokines including IL-1ß and attenuated liver inflammation and renal injury of mice with sepsis, concomitant with reduced generation of caspase-1p10 and GSDMD-NT in the liver and kidney. Together, we demonstrate that theaflavin suppresses NLRP3 inflammasome activation and pyroptosis by protecting mitochondrial function, thus mitigating acute gouty peritonitis and bacterial sepsis in mice, highlighting a potential application in treating NLRP3 inflammasome-related diseases.

Nigericin Induces Apoptosis in Primary Effusion Lymphoma Cells by Mitochondrial Membrane Hyperpolarization and ß-Catenin Destabilization.

BACKGROUND/AIM: Primary effusion lymphoma (PEL) is classified as a rare non-Hodgkin's B-cell lymphoma that is caused by Kaposi's sarcoma-associated herpesvirus (KSHV); PEL cells are latently infected with KSHV. PEL is frequently resistant to conventional chemotherapies. Therefore, the development of novel therapeutic agents is urgently required. Nigericin, a H+ and K+ ionophore, possesses unique pharmacological effects. However, the effects of nigericin on PEL cells remain unknown. MATERIALS AND METHODS: We examined the cytotoxic effects of the K+ ionophores, nigericin, nonactin, and valinomycin, on various B-lymphoma cells including PEL. We also evaluated ionophore-induced changes in signaling pathways involved in KSHV-induced oncogenesis. Moreover, the effects of nigericin on mitochondrial membrane potential and viral reactivation in PEL were analyzed. RESULTS: Although the three tested ionophores inhibited the proliferation of several B-lymphoma cell lines, nigericin inhibited the proliferation of PEL cells compared to KSHV-negative cells. In PEL cells, nigericin disrupted the mitochondrial membrane potential and caused the release of cytochrome c, which triggered caspase-9-mediated apoptosis. Nigericin also induced both an increase in phosphorylated p38 MAPK and proteasomal degradation of ß-catenin. Combination treatment of nigericin with the p38 MAPK inhibitor SB203580 potentiated the cytotoxic effects towards PEL cells, compared to either compound alone. Meanwhile, nigericin did not influence viral replication in PEL cells. CONCLUSION: Nigericin induces apoptosis in PEL cells by mitochondrial dysfunction and down-regulation of Wnt/ß-catenin signaling. Thus, nigericin is a novel drug candidate for treating PEL without the risk of de novo KSHV infection.

Corilagin Restrains NLRP3 Inflammasome Activation and Pyroptosis through the ROS/TXNIP/NLRP3 Pathway to Prevent Inflammation.

Corilagin, a gallotannin, shows excellent antioxidant and anti-inflammatory effects. The NLRP3 inflammasome dysfunction has been implicated in a variety of inflammation diseases. However, it remains unclear how corilagin regulates the NLRP3 inflammasome to relieve gouty arthritis. In this study, bone marrow-derived macrophages (BMDMs) were pretreated with lipopolysaccharide (LPS) and then incubated with NLRP3 inflammasome agonists, such as adenine nucleoside triphosphate (ATP), nigericin, and monosodium urate (MSU) crystals. The MSU crystals were intra-articular injected to induce acute gouty arthritis. Here we showed that corilagin reduced lactate dehydrogenase (LDH) secretion and the proportion of propidium iodide- (PI-)stained cells. Corilagin suppressed the expression of N-terminal of the pyroptosis executive protein gasdermin D (GSDMD-NT). Corilagin restricted caspase-1 p20 and interleukin (IL)-1ß release. Meanwhile, corilagin attenuated ASC oligomerization and speck formation. Our findings confirmed that corilagin diminished NLRP3 inflammasome activation and macrophage pyroptosis. We further discovered that corilagin limited the mitochondrial reactive oxygen species (ROS) production and prevented the interaction between TXNIP and NLRP3, but ROS activator imiquimod could antagonize the inhibitory function of corilagin on NLRP3 inflammasome and macrophage pyroptosis. Additionally, corilagin ameliorated MSU crystals induced joint swelling, inhibited IL-1ß production, and abated macrophage and neutrophil migration into the joint capsule. Collectively, these results demonstrated that corilagin suppressed the ROS/TXNIP/NLRP3 pathway to repress inflammasome activation and pyroptosis and suggest its potential antioxidative role in alleviating NLRP3-dependent gouty arthritis.

STING mediates neuroinflammatory response by activating NLRP3-related pyroptosis in severe traumatic brain injury.

Long-term neurological deficits after severe traumatic brain injury (TBI), including cognitive dysfunction and emotional impairments, can significantly impair rehabilitation. Glial activation induced by inflammatory response is involved in the neurological deficits post-TBI. This study aimed to investigate the role of the stimulator of interferon genes (STING)-nucleotide-binding oligomerization domain-like receptor pyrin domain-containing-3 (NLRP3) signaling in a rodent model of severe TBI. Severe TBI models were established using weight-drop plus blood loss reinfusion model. Selective STING agonist ADU-S100 or antagonist C-176 was given as a single dose after modeling. Further, NLRP3 inhibitor MCC950 or activator nigericin, or caspase-1 inhibitor VX765, was given as an intracerebroventricular injection 30 min before modeling. After that, a novel object recognition test, open field test, force swimming test, western blot, and immunofluorescence assays were used to assess behavioral and pathological changes in severe TBI. Administration of C-176 alleviated TBI-induced cognitive dysfunction and emotional impairments, neuronal loss, and inflammatory activation of glia cells. However, the administration of STING agonist ADU-S100 exacerbated TBI-induced behavioral and pathological changes. In addition, STING activation exacerbated pyroptosis-associated neuroinflammation via promoting glial activation, as evidenced by increased cleaved caspase-1 and GSDMD N-terminal expression. In contrast, the administration of C-176 showed anti-pyroptotic effects. The neuroprotective effects of C-176 were partially reversed by the NLRP3 activator, nigericin. Collectively, glial STING is responsible for neuroinflammation post-TBI. However, pharmacologic inhibition of STING led to a remarkable improvement of neuroinflammation partly through suppressing NLRP3 signaling. The STING-NLRP3 signaling is a potential therapeutic target in TBI-induced neurological dysfunction.

Dimethyl fumarate ameliorates autoimmune hepatitis in mice by blocking NLRP3 inflammasome activation.

Dimethyl fumarate (DMF) is a fumaric acid derivative clinically approved for the treatment of some inflammatory diseases, but the underlying mechanism for its therapeutic effects remains incompletely understood. NLR family pyrin domain containing 3 (NLRP3) inflammasome activation has critical roles in innate immune responses to various infections and sterile inflammations. In this study, we aimed to explore whether DMF affects auto-immune hepatitis (AIH) in mice induced by concanavalin A (Con A) by modulating NLRP3 inflammasome activation. The results showed that DMF suppressed the activation of NLRP3 inflammasome activation in lipopolysaccharide-primed murine bone marrow-derived macrophages upon ATP or nigericin treatment, as evidenced by reduced cleavage of pro-caspase-1, release of mature interleukin-1ß (IL-1ß) and generation of gasdermin D N-terminal fragment (GSDMD-NT). DMF also greatly reduced ASC speck formation upon the stimulation of nigericin or ATP, indicating its inhibitory effect on NLRP3 inflammasome assembly. Consistent with reduced generation of GSDMD-NT, ATP or nigericin-induced pyroptosis was markedly suppressed by DMF. Moreover, DMF treatment alleviated mitochondrial damage induced by ATP or nigericin. Interestingly, all these effects were reversed by the protein kinase A (PKA) pathway inhibitors (H89 and MDL-12330A). Mechanistically, DMF enhanced PKA signaling and thus increased NLRP3 phosphorylation at PKA-specific sites to attenuate its activation. Importantly, DMF decreased serum levels of inflammatory cytokines and ameliorated liver injury in Con A-induced AIH of mice, concomitant with reduced the generation of caspase-1p10 and GSDMD-NT and alleviating mitochondrial aggregation in the liver. Collectively, DMF displayed anti-inflammatory effects by inhibiting NLRP3 inflammasome activation likely through regulating PKA signaling, highlighting its potential application in treating AIH.

Potential of nobiletin against Alzheimer's disease through inhibiting neuroinflammation.

OBJECTIVE: This study aimed to explore the mechanism of Nobiletin attenuating Alzheimer's disease (AD) by inhibiting neuroinflammation. METHODS: The expression of inflammatory cytokines and HMGB-1 in serum of AD patients were examined. Microglia (MGs) were treated with different doses of Nobiletin before LPS and Nigericin induction. Cell viability and apoptosis were determined by CCK-8 and TUNEL assays, respectively. APP/PS1 mice were gavaged with Nobiletin, and Morris water maze (MWM) was established to record swimming speed, escape latency, the number of platform crossings, and time spent in the platform quadrant. MGs activation in brain tissues was evaluated by immunofluorescence. The expression of pyroptosis-related proteins, inflammatory cytokines, and HMGB-1 was determined in the hippocampus and MGs. RESULTS: The levels of inflammatory cytokines and HMGB-1 were high in serum of AD patients. Treatment with different concentrations of Nobiletin prominently enhanced cell viability and reduced apoptosis and the expression of inflammatory cytokine and pyroptosis-related proteins in LPS + Nigericin-induced MGs. Gavage of different doses of Nobiletin into APP/PS1 mice shortened the escape latency in mice, diminished MGs activation in brain tissues, and remarkably elevated the number of platform crossings and the time spent in the platform quadrant without obvious change in swimming speed, suggesting that Nobiletin improved the spatial learning and memory abilities in APP/PS1 mice. The expression of pyroptosis-related proteins, HMGB-1, and inflammatory cytokines was decreased dramatically by Nobiletin in the hippocampus of APP/PS1 mice. CONCLUSIONS: Nobiletin can inhibit neuroinflammation by inhibiting HMGB-1, pyroptosis-related proteins, and inflammatory cytokines, thus mitigating AD.

Nigericin exerts anticancer effects through inhibition of the SRC/STAT3/BCL-2 in osteosarcoma.

The treatment of osteosarcoma has reached a bottleneck period in recent 30 years, there is an urgent need to find new drugs and treatment methods. Nigericin, an antibiotic derived from Streptomyces hygroscopicus, has exerted promising antitumoral effect in various tumors. The anticancer effect of Nigericin in human osteosarcoma has never been reported. In the present study, we explored the anticancer effects of Nigericin in osteosarcoma in vitro and in vivo. Our results showed that nigericin treatment significantly reduced tumor cell proliferation in dose-dependent and time-dependent in human osteosarcoma cells. Nigericin can inhibit cell growth of osteosarcoma cells, in addition to S-phase cycle arrest, the nigericin induces apoptosis. Furthermore, bioinformatics predicted that Nigericin exerts anticancer effects through inhibiting SRC/STAT3 signaling pathway in osteosarcoma. The direct binding between SRC and activator of transcription 3 (STAT3) was confirmed by Western blot. Nigericin can down regulate STAT3 and Bcl-2. In order to further elucidate the inhibitory effect of nigericin on SRC/STAT3/Bcl-2 signal transduction mechanism, we established human osteosarcoma cancer cells stably expressing STAT3. Western blot confirmed that nigericin exerts anticancer effects on human osteosarcoma cancer cells by directly targeting STAT3. In addition, Nigericin can significantly inhibit tumor migration and invasion. Finally, Nigericin inhibits tumor growth in a mouse osteosarcoma model. The nigericin targeting the SRC/STAT3/BCL-2 signaling pathway may provide new insights into the molecular mechanism of nigericin on cancer cells and suggest its possible clinical application in osteosarcoma.

Nigericin is effective against multidrug resistant gram-positive bacteria, persisters, and biofilms.

Multidrug-resistant (MDR) bacteria pose a significant clinical threat to human health, but the development of antibiotics cannot meet the urgent need for effective agents, especially those that can kill persisters and biofilms. Here, we reported that nigericin showed potent bactericidal activity against various clinical MDR Gram-positive bacteria, persisters and biofilms, with low frequencies of resistance development. Moreover, nigericin exhibited favorable in vivo efficacy in deep-seated mouse biofilm, murine skin and bloodstream infection models. With Staphylococcus aureus, nigericin disrupted ATP production and electron transport chain; cell death was associated with altered membrane structure and permeability. Obtaining nigericin-resistant/tolerant mutants required multiple rounds of challenge, and, cross-resistance to members of several antimicrobial classes was absent, probably due to distinct nigericin action with the GraSR two-component regulatory system. Thus, our work reveals that nigericin is a promising antibiotic candidate for the treatment of chronic or recurrent infections caused by Gram-positive bacteria.

Evidence of nigericin as a potential therapeutic candidate for cancers: A review.

Emerging studies have shown that nigericin, an H+, K+ and Pb2+ ionophore, has exhibited a promising anti-cancer activity in various cancers. However, its anti-cancer mechanisms have not been fully elucidated. In this review, the recent progresses on the use of nigericin in human cancers have been summarized. By exchanging H+ and K+ across cell membranes, nigericin shows promising anti-cancer activities in in vitro and in vivo as a single agent or in combination with other anti-cancer drugs through decreasing intracellular pH (pHi). The underlying mechanisms of nigericin also include the inactivation of Wnt/ß-catenin signals, blockade of Androgen Receptor (AR) signaling, and activation of Stress-Activated Protein Kinase/c-Jun N-terminal Kinase (SAPK/JNK) signaling pathways. In many cancers, nigericin is proved to specifically target putative Cancer Stem Cells (CSCs), and its synergistic effects on photodynamic therapy are also reported. Other mechanisms of nigericin including influencing the mitochondrial membrane potentials, inducing an increase in drug accumulation and autophagy, controlling insulin accumulation in nuclei, and increasing the cytotoxic activity of liposome-entrapped drugs, are also discussed. Notably, the potential adverse effects such as teratogenic effects, insulin resistance and eryptosis shall not be ignored. Taken together, these reports suggest that treatment of cancer cells with nigericin may offer a novel therapeutic strategy and future potential of translation to clinics.

Nigericin is a potent inhibitor of the early stage of vaccinia virus replication.

Poxviruses remain a significant public health concern due to their potential use as bioterrorist agents and the spread of animal borne poxviruses, such as monkeypox virus, to humans. Thus, the identification of small molecule inhibitors of poxvirus replication is warranted. Vaccinia virus is the prototypic member of the Orthopoxvirus genus, which also includes variola and monkeypox virus. In this study, we demonstrate that the carboxylic ionophore nigericin is a potent inhibitor of vaccinia virus replication in several human cell lines. In HeLa cells, we found that the 50% inhibitory concentration of nigericin against vaccinia virus was 7.9 nM, with a selectivity index of 1038. We present data demonstrating that nigericin targets vaccinia virus replication at a post-entry stage. While nigericin moderately inhibits both early vaccinia gene transcription and translation, viral DNA replication and intermediate and late gene expression are severely compromised in the presence of nigericin. Our results demonstrate that nigericin has the potential to be further developed into an effective antiviral to treat poxvirus infections.

Phenotypic and genotypic changes in Salmonella enterica subsp. enterica serotype typhimurium during passage in intestines of broiler chickens fed on diets that included ionophore anticoccidial supplements.

The effect of continuous in-feed administration of anticoccidial agents on antimicrobial sensitivity and the level of bacterial shedding in poultry experimentally infected with Salmonella enterica subsp. enterica serotype Typhimurium definitive type 104 (DT104) were investigated. On day 0, 1,200 1-day-old Salmonella-free broiler chicks were placed into 50 pens, and the pens were randomly allocated to one of five treatments: nonsupplemented (negative control; T1), monensin at 120 mg/kg of diet (T2), salinomycin at 60 mg/kg of diet (T3), semduramicin at 20 mg/kg of diet (T4), or semduramicin at 25 mg/kg of diet (T5). Each bird was inoculated with a well-characterized strain of serotype Typhimurium DT104 on day 10. On day 49, the birds were euthanatized humanely. Bulk fecal samples were collected on days 13, 43, and 48 and were examined for organisms which had acquired resistance. The genetic basis of acquired resistance was determined from representative samples of isolates. Of 784 Salmonella-selective plates supplemented with antimicrobial agents, only 33 showed growth. These isolates came from all treatment regimens, including the nonsupplemented control. A number of phenotypic changes were observed; these included changes in motility, phage type, and agglutination properties. Supplementation of the diet with an anticoccidial drug does not appear to affect antimicrobial resistance or the level of excretion of salmonellae. Most of the changes observed do not seem to be related to the presence of a supplement in feed. Salmonellae appear to be capable of acquiring antimicrobial resistance and phenotypic changes independently of specific antimicrobial selection pressures.

In pursuit of drugs for American trypanosomiasis: evaluation of some "standards" in a mouse model.

Forty-nine "standard" compounds known to be useful in the treatment of other diseases were tested for their suppressive activity against the trypomastigotes of Trypanosoma cruzi-infected mice. The most active was the antidepressant protriptyline, which was almost three times as effective as the reference drug, nifurtimox. A major value of the present data is to demonstrate the refractoriness of the T. cruzi parasite against many of the drug standards that have known biological activity.

Carboxylic ionophores in malaria chemotherapy: the effects of monensin and nigericin on Plasmodium falciparum in vitro and Plasmodium vinckei petteri in vivo.

Chloroquine is widely used in malaria chemotherapy. Due to its weak base properties, this drug accumulates in the parasite food vacuole where it acts initially by raising the pH of this organelle, thereby reducing the digestion of hemoglobin by the parasite and preventing its growth. Nevertheless, alkalinization of the food vacuole and inhibition of lysosomal protein degradation could also be achieved by means of carboxylic ionophores such as monensin and nigericin. These drugs intercalate into intracellular organelle membranes and exchange protons for K+ or Na+. In the present study, we show that monensin and nigericin exhibit in vitro intrinsic antimalarial activities at nanomolar and picomolar range, respectively, on P.falciparum and thereby appear 25 fold and 30,000 fold more potent than chloroquine. The very low IC50 values exhibited by these two ionophores prompted us to test their antimalarial activities in vivo on Plasmodium vinckei petteri. We found that the ED50 and ED90 values were respectively 1.1mg/kg and 3.5 mg/kg for monensin; 1.8 mg/kg and 4.6 mg/kg for nigericin. In addition, when treated with monensin at 10 mg/kg, 100% of the infected mice were cured. Interestingly, nigericin can be combined with monensin and we show that this combination is synergic. Thus, this finding would allow the use of lower doses of these ionophores and prevent occurrence of drug resistance. Carboxylic ionophores can be viewed as a new strategy in malaria chemotherapy.

Efficacy of semduramicin and salinomycin against Eimeria maxima in a laboratory test using two levels of oocyst inocula.

The anticoccidial efficacies of semduramicin and salinomycin against five field isolates of Eimeria maxima in broiler chickens were compared in five trials. Uninfected, unmedicated; infected, unmedicated; infected, 25 ppm semduramicin; and infected, 66 ppm salinomycin treatments were assigned to battery cages using a randomized, complete block design. Two levels of inocula, 10(3) and 10(4) oocysts per bird, were used in each trial in the infected treatments, creating a total of seven treatments per trial. Each treatment consisted of five replicate cages of eight broiler cockerels each. Medications were given in the feed continuously for 7 d beginning 24 h before inoculation. Response variables measured included bird weight gain by pen, feed consumption, feed conversion, plasma carotenoid concentrations, and coccidial lesion score. By using two levels of inocula it was demonstrated that the efficacy of each anticoccidial was equal to or greater than 90% in controlling these E. maxima isolates. It was also demonstrated that 25 ppm semduramicin was more efficacious than 66 ppm salinomycin based on improvements in weight gain, feed conversion, plasma carotenoid concentrations, and coccidial lesion control.

[Herpes simplex infection in newborn infants]. / Kherpes simpleks infektsiia u novorodeni detsa.

Six cases of proven herpes simplex infection in newborn babies are reported. Different clinical forms are observed: three babies with multisystem disease that attacked viscera and other three with central nervous system localisation. All six mothers have negative history for being carrier of herpes simplex virus. The babies are treated with Herpesbulin, Pandavir and Zovirax. One of them died with meningoencephalitis. The outcome at the age of three months after birth of the other 5 babies is: 2 babies are healthy, three developed late sequelae.

Antitumor activity of nigericin and 5-(N-ethyl-N-isopropyl)amiloride: an approach to therapy based on cellular acidification and the inhibition of regulation of intracellular pH.

The extracellular pH (pHe) in solid tumors is frequently lower than the pHe in normal tissues, but the intracellular pH (pHi) is regulated to physiological levels. Cell killing can be achieved in an acidic environment in tissue culture by nigericin, which acidifies cells by transporting H+ from the extracellular space into the cytoplasm; this cell killing can be enhanced when used with 5-(N-ethyl-N-isopropyl)amiloride (EIPA), a potent inhibitor of membrane-based Na+/H+ exchange, which plays a major role in the regulation of pHi (R. P. Maidorn; E. J. Cragoe; I. F. Tannock, Br. J. Cancer 67:297-303; 1993). We have therefore assessed the ability of nigericin and EIPA to kill cells in two murine solid tumors (the KHT fibrosarcoma and the EMT-6 sarcoma). Hydralazine, which reduces tumor blood flow, or glucose, which stimulates glycolysis leading to accumulation of lactate, were also administered to mice to lower pHe in the tumors. We observed only a small decrease in the surviving fractions of cells in the tumors when tolerated doses of nigericin and EIPA were given IP to tumor-bearing mice. When nigericin and EIPA were combined with administration of hydralazine, the surviving fraction of cells in both tumors was reduced by a factor of 0.01, but there were minimal effects on growth delay. Administration of glucose with nigericin and EIPA led to a smaller reduction in surviving fraction of the KHT tumor (by approximately 0.1), although glucose was more effective than hydralazine in lowering the mean tumor pHe. When KHT tumors were treated with 15 Gy X-rays followed immediately by nigericin, EIPA, and hydralazine, a reduced surviving fraction as well as an increase in tumor growth delay was observed compared to radiation alone; however, there was little evidence to suggest that these agents were selectively toxic to the cells that survived radiation. Nigericin and EIPA, with or without hydralazine, had minimal effects on normal tissues, as assessed by changes in body weight, number of leukocytes, and serum creatinine levels. We conclude that pharmacological effects to acidify cells and to prevent regulation of pHi under the acidic conditions that exist in solid tumors can lead to moderate levels of cell killing, if additional strategies are used to lower tumor pHe.

Anticoccidial efficacy of semduramicin. 2. Evaluation against field isolates including comparisons with salinomycin, maduramicin, and monensin in battery tests.

The efficacy of semduramicin (AVIAX), a novel polyether ionophore, was profiled in a series of 57 battery tests conducted in the United States and the United Kingdom. The studies employed mixed and monospecific infections of Eimeria acervulina, Eimeria mivati/Eimeria mitis, Eimeria brunetti, Eimeria maxima, Eimeria necatrix, and Eimeria tenella derived from North American and European field isolates. Ten-day-old broiler cockerels in pens of 8 to 10 birds were continuously medicated in feed beginning 24 h before challenge in tests of 6 to 8 days' duration. At the use level of 25 ppm, semduramicin effectively controlled mortality, lesions, and weight gain depression that occurred in unmedicated, infected controls for all species. In comparison with 60 ppm salinomycin, semduramicin significantly (P < .05) improved weight gain against E. brunetti and E. tenella, lesion control against E. brunetti and E. maxima, and the control of coccidiosis mortality against E. tenella. Salinomycin was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions for E. acervulina. Maduramicin at 5 ppm was inferior (P < .05) to semduramicin in control of E. acervulina and E. maxima lesions, but was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions in E. tenella infections. The data indicate that semduramicin at 25 ppm is well tolerated in broilers and possesses broad spectrum anticoccidial activity.

Efficacy of semduramicin and salinomycin against different stages of Eimeria tenella and E. acervulina in the chicken.

The efficacy of a new ionophore, semduramicin, was compared with salinomycin in a series of in ovo and in vivo trials. Semduramicin was more efficacious than salinomycin against Eimeria tenella sporozoites as judged by oocyst production in embryonated eggs. When the two drugs were given in ovo at 93 h post inoculation (PI), both drugs exerted some effect against late schizogonous stages of E. tenella. In three battery studies, semduramicin (25 ppm) and salinomycin (60 and 66 ppm) were tested against E. tenella and E. acervulina. Medicated feed was withdrawn at 24-h intervals PI to study the stage of action of the anticoccidials. In E. tenella infected chickens, both anticoccidials exerted their maximum effect on weight gain and feed:gain ratio through the first 72 h PI. Semduramicin was more effective than salinomycin in controlling E. tenella lesions and coccidiosis mortality. With E. acervulina, both drugs acted similarly on early life cycle stages and no improvement in performance was recorded when medicated feed was given for longer than 72 h. Semduramicin was more effective than salinomycin in controlling E. acervulina lesions.

Anticoccidial efficacy of semduramicin in battery studies with laboratory isolates of coccidia.

The anticoccidial activity of semduramicin against laboratory isolates of five species of poultry Eimeria was investigated. In laboratory scale battery trials, semduramicin at 20 to 30 ppm demonstrated broad-spectrum anticoccidial efficacy equivalent to salinomycin at 60 ppm. Also, semduramicin at 25 ppm was fed to uninfected cockerels in batteries for 21 days, and growth rate and feed efficiency were found to be equivalent to birds fed salinomycin at 60 ppm. Semduramicin was well tolerated when coadministered with tiamulin. Semduramicin demonstrated the same activity whether produced by semisynthesis or by direct fermentation.